Flight-icing simulator

ABSTRACT

This invention supplies a flight-icing simulator to train the pilots with skills under flight-icing conditions. This simulator is composed of several modules to provide pilots the information of ice distribution and strength on aircrafts, the distance of the aircraft to the icing dangerous zone, the perturbation of the points with feedback function, etc.

TECHNICAL FIELD OF THE INVENTION

This invention relates aerospace domain. Particularly, it is a flight-icing simulator for simulating the state of an aircraft being or being on the point of icing in flight. It is used to train pilots to control and take steps under this state.

TECHNICAL BACKGROUND

At a certain attitude, the SWD (Supercooled Water Droplets) in atmosphere, which are at temperature below the freezing point but exist in form of particles, may impact on the surfaces of flying aircrafts. If the LWC (Liquefied Water Content) of SWD in atmosphere is high, the water film can adhere on aircraft surfaces and accrete into ice if aircraft flying attitude is up to 4000 meters. This phenomenon is called the flight-icing. Ice accretion on some critical control surfaces of aircraft, such as wing, stabilizer, engine inlet, engine blades, etc. has a significant impact on operation and controllability of aircraft. For examples, it may shift the gravity center of aircraft, freeze movable components, result in substantial decrease of lift and increase in drag, reduce stall margin. The accreted ice on the nacelle in front of engine may be ingested into engine inlet causing thrust loss even flame out. According to statistics of aircraft flight safety, the flight-icing cases count more than 60% of aviation disaster.

Modern aircrafts generally install the de-icing system, which routinely starts the electrical heating equipment through the control of the feedback from the icing sensors on the critical surfaces of aircraft, to finish the de- and anti-icing work for aircrafts in flight and. Statistically showing that the de-icing system keeps about 80% aircraft flying time means that the possibility of flight-icing for aircrafts is very high.

For flight safety, aircrafts must fly in a safe mode when encountering the flight-icing conditions in atmosphere. Modern aircrafts fly under Instrument flight rule (IFR), which demands the pilots to follow all kinds of commands from instruments or control aircrafts in an automatic mode. When aircrafts meet the flight-icing conditions, the pilots and the de-icing systems must execute their different tasks. It is necessary to train the pilots the ability to accomplish the tasks in the same situations as in flight. The purpose of this invention is to improve pilots' ability to correctly evaluate, judge situations and execute corresponding operations. The training gives the pilots the memory and feeling of operation sequence through supplying the different visual signals. Besides, the training can build for the pilots a spectacle of pressure and affection under flight-icing in mentality.

Supply a simulator with functions mentioned above for training pilots in land is very important. It is called the flight-icing simulator.

SUMMARY OF THE INVENTION

This invention supplies a flight-icing simulator to train the pilots with skills under flight-icing conditions, such as to do de-icing operation and avoid dangerousness. This simulator provides pilots the information of ice distribution and strength on aircrafts, the distance of the aircraft to the icing dangerous zone, the perturbation of the points with feedback function. This simulator is composed of several modules. Those modules and their functions are described following.

-   -   SM (Startup Module), which can select one training scheme and         start all other modules.     -   ACDM (Atmosphere Condition Database Module), which storages         database of LWC, SWD scale distribution, atmosphere pressure,         convection velocity, temperature and humidity, etc.     -   FPMM (Flying Parameter Memory Module), which storages different         aircraft configurations, flying state information, such as         flight attitude, speed, accelerated speed, angle of attack,         angle of deviation, angle of roll, etc. for different aircrafts.     -   FSSM (Flight-icing State Simulation Module), which calculates         ice distribution and strength based on information from ACDM and         FPMM. This module includes the following four units.         -   (1) OSOBMU (Original Snapshot's Orthogonal Base Memory Unit)         -   (2) OSCCMMU (Original Snapshot's Characteristic Coefficient             Matrix Memory Unit)         -   (3) IU (Interpolation Unit)         -   (4) ISCU (Icing State Calculation Unit)     -   ISMSM (Icing Sensor Matrix Simulation Module), which calculates         the variation of the vibration frequency of the vibrator of the         virtual icing sensors arranged on the critical points of         aircraft surfaces based on information from FSSM.     -   FESM (Flight-icing Effect Simulation Module), which calculates         the additional force and momentum acting on aircraft induced by         flight-icing. This module includes the following three units.         -   (1) LPSU (Loading Point Selection Unit)         -   (2) FIU (Force Integration Unit)         -   (3) MIU (Momentum Integration Unit)     -   ASM (Alarm Simulation Module), which starts an alarm system         according to safety judgment criterion comparing to information         of icing distribution and strength from FSSM.     -   EHDSM (Electrical Heating De-icing Simulation Module), which         determines the output heat to do de-icing based on the predicted         amount of ice in FSSM and ASM. This module includes the         following three units.         -   (1) MSHTCU (Metal Skin Heat Transfer Calculation Unit)         -   (2) ILHCCU (Ice Layer Heat Conduction Calculation Unit)         -   (3) DECU (De-icing Effect Calculation Unit)     -   DCM (Distance Calculation Module), which calculates the distance         to the icing dangerous zone. This module includes the following         three units.         -   (1) DU (Database Unit for the relationship of air convection             velocity and LWC of SWD)         -   (2) IU (Interpolation Unit)         -   (3) DCU (Distance Calculation Unit)     -   VSM (Visual Simulation Module), which presents cloud and ice         layer on aircraft surface based on type of aircraft in FPMM and         predicted ice distribution in FSSM and ASM.     -   PWAM (Pilot Work Area Module), which is a real motor driven         chair.     -   AIPM (Aviation Instrument Panel Module), which is a real         aviation instrument panel including the screen displaying         information from ASM an EHDSM's running     -   DDTSM (Dynamic Data Transmission Simulation Module), which         transfers all signals about flying state and other information         such as force, momentum to VSM, PWAM, AIPM, etc.     -   BBM (Black Box Module), which functions to record all the         information in flight.

BRIEF DESCRIPTION OF FIGURES

FIG. 1 the connection relation among all the modules in flight-icing simulator

FIG. 2 the connection of different units in FSSM 4

FIG. 3 the relationship of the units in EHDSM 9

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

An embodiment of a flight-icing simulator according to the invention is illustrated following. It is a simulator to train pilots skills under flight-icing conditions.

The FIG. 1 illustrates the connection relation among all the modules in this simulator, where includes SM (Startup Module) 1, ACDM (Atmosphere Condition Database Module) 2, FPMM (Flying Parameter Memory Module) 3, FSSM (Flight-icing State Simulation Module) 4, ISMSM (Icing Sensor Matrix Simulation Module) 5, FESM (Flight-icing Effect Simulation Module) 6, DDTSM (Dynamic Data Transmission Simulation Module) 7, ASM (Alarm Simulation Module) 8, EHDSM (Electrical Heating De-icing Simulation Module) 9, DCM (Distance Calculation Module) 10, VSM (Visual Simulation Module) 11, PWAM (Pilot Work Area Module) 12, AIPM (Aviation Instrument Panel Module) 13, BBM (Black Box Module) 14.

-   -   SM 1 has a delay circuit, which firstly functions to load power,         reset, warm up for all other modules. After this task, it comes         into a selection mode, which decides precision, error level,         sampling interval, heating method, atmosphere conditions,         aircraft type, flying state, and training case. Finally, it set         an initial time as timing reference for simulation.     -   ACDM 2 storages database including LWC, SWD scale distribution,         atmosphere pressure, convection velocity, temperature and         humidity in three-dimensional spatial grid points with 1         killermeter increment. The spatial domain is large enough to         cover the aircraft flying range during the flight-icing         simulation. For the different training case, there exists the         refined database backup of atmosphere condition from         interpolation.     -   FPMM 3 storages different aircraft configurations and locations         of force and icing sensor in three-dimensional curved surface         grid points. It also saves flying state information, such as         flight attitude, speed, accelerated speed, angle of attack,         angle of deviation, angle of roll. there exists the refined         database backup of curved surface grid points from         interpolation.     -   FSSM 4 calculates ice distribution and strength from information         from ACDM 2 and FPMM 3. The calculation gives the results within         the sampling interval decided by SM 1. The results are presented         as the form of data table built by the ice thickness on the         three-dimensional grid points on aircraft surface and time         points during the sampling interval. Some results for those         points locating the icing sensor are tabled extra. This module         includes the following four units: OSOBMU(Original Snapshot's         Orthogonal Base Memory Unit), OSCCMMU(Original Snapshot's         Characteristic Coefficient Matrix Memory Unit), IU         (Interpolation Unit), and ISCU(Icing State Calculation Unit).

The so-called original snapshot is a set of data from test in flight, wind tunnel test and numerical simulation based on computational fluid dynamics. The original snapshot for the flight-icing is in the form of multi-dimensional data array about iced aircraft surface coordinators. For example, a variable set of an original snapshot is written as the form of

{U^(i) _(j)}, i=1,2, . . . ,ns, j=1,2, . . . , N,  (1)

where ns is the number of the original snapshot; N is the number of points. Formally, the original snapshot is composed of ns sets of N-dimensional vector. For each vector, U is the coordinate vector of aircraft surface points. The dimension for each vector {U^(i) _(j)} should be m·N, where m is the dimension of U. the original snapshot itself constructs several training cases and the interpolation operation to them can takes shape the flight-icing state under different flight conditions. The FIG. 2 illustrates the connection of different units in this module.

OSOBMU storages the set of original snapshot's orthogonal base matrix, which are ns sets of N-dimensional orthogonal base vector. formally, it is

{φ^(i) _(j)}, i=1,2, . . . ,ns, j=1,2, . . . , N,  (2)

OSCCMMU storages the original snapshot's characteristic coefficient matrix, which is a ns rows and ns columns square matrix. Specially, it is

$\begin{matrix} {\begin{bmatrix} \alpha_{1}^{1} & \alpha_{2}^{1} & \vdots & \vdots & \vdots & \alpha_{ns}^{1} \\ \alpha_{1}^{2} & \alpha_{2}^{2} & \vdots & \vdots & \vdots & \alpha_{ns}^{2} \\ \vdots & \vdots & \; & \; & \; & \vdots \\ \vdots & \vdots & \; & \; & \; & \vdots \\ \vdots & \vdots & \; & \; & \; & \vdots \\ \alpha_{1}^{ns} & \alpha_{2}^{ns} & \vdots & \vdots & \vdots & \alpha_{ns}^{ns} \end{bmatrix}.} & (3) \end{matrix}$

IU runs interpolation operation to the original snapshot's characteristic coefficient in OSCCMMU, if the selected training case is not one of the original snapshots, based on the data from ACDM 2 and FPMM 3, to find the characteristic coefficient α₁ ^(k),α₂ ^(k), . . . α_(ns) ^(k) for new training case.

ISCU finds the iced aircraft surface coordinators by multiplying the interpolated characteristic coefficient α₁ ^(k),α₂ ^(k), . . . α_(ns) ^(k) in IU with the original snapshot's orthogonal base in OSOBMU, which means

$\begin{matrix} {{\left\{ U_{j}^{k} \right\} = {\sum\limits_{i = 1}^{ns}\; {\alpha_{i}^{k}\left\{ \phi_{j}^{k} \right\}}}},{j = 1},{N.}} & (4) \end{matrix}$

The accuracy of all mathematic operation is decided in SM 1. Since the time delay used for calculation in this module makes the flight-icing prediction cannot work in real-time, it needs to be recorded. The ice capacity on aircraft surfaces is discretized at the points matched with heater. A table constructed with the heater number list and the discretized ice capacity is generated; then it is sent to EHDSM 9.

-   -   ISMSM 5, receiving information from SM 1, ACDM 2, FPMM 3, and         FSSM 4, simulates the ice distribution and strength on the         points of icing sensors. The working principle of real icing         sensor is that icing can change the vibration frequency of the         vibrator of the icing sensor. In the invention, the virtual         icing sensor is a circuit which is pre-calibrated according to         the relationship of the icing capacity and the vibration         frequency of the vibrator. The circuit is input the information         about the icing capacity calculated in FSSM 4 and outputs the         analogy quantity about vibration frequency. The analogy quantity         is sent to ASM 8 and AIPM 13.     -   FESM 6, receiving information from SM 1, ACDM 2, FPMM 3, and         FSSM 4, calculates the additional force and momentum acting on         aircraft induced by flight-icing and sends the results to PWAM         12 and AIPM 13. This module includes the following three units:         LPSU (Loading Point Selection Unit), FIU (Force Integration         Unit), and MIU (Momentum Integration Unit). LPSU transfers the         information from ISMSM 5 into volume and weight at each point.         FIU integrate all the weight to get the whole force induced by         icing. MIU calculates momentum around aerodynamic center of         aircraft.     -   ASM 8 starts an alarm circuit when the voltage value input         presenting the vibration frequency of icing sensor vibrator from         ISMSM 5 is higher than the value of safety voltage. The alarm         time needs to be recorded, since the time delay in FSSM 4 needs         to be removed from the alarm time to catch up real-time alarm         like real aircraft under flight-icing. The real icing capacity         on aircraft surface should be modified according to time         reduction, which can be fulfilled by using backward         interpolation of data in each icing sensors along time sequence.         The modified data are sent to VSM 11 and AIPM 13.     -   EHDSM 9 determines the output heat to do de-icing based on the         predicted amount of ice in FSSM 4. There are two heating modes.         The steady mode doesn't consider the new ice increasing during         heating; while the dynamic mode needs to do it. This module         includes the following three units: MSHTCU(Metal Skin Heat         Transfer Calculation Unit), ILHCCU(Ice Layer Heat Conduction         Calculation Unit), and DECU(Deicing Effect Calculation Unit).         The FIG. 3 shows the relationship of the units in this module.         MSHTCU simulates heat conduction and a conjugate heat transfer         processes. Heating comes under metal skin inside where         temperature distribution is linear. At the interface of metal         skin and ice, heat is transferred reciprocally, which is         conjugate heat transfer. ILHCCU simulates a heat transfer where         temperature distribution inside ice layer is linear and the         temperature at the interface of ice and air is atmosphere one.         DECU feeds back the voltage values indicating the change of ice         capacity during heating period to ASM 8, which judges the         electrical heat is to be shut down when the voltage values is         lower than the safety value.     -   DCM 10 calculates the distance to the icing dangerous zone         through information from SM 1, ACDM 2, FPMM 3 and sends result         to AIPM 13. This module includes three units: DU(Database Unit         for the relationship of air convection velocity and LWC of SWD),         IU(Interpolation Unit), and DCU(Distance Calculation Unit). DU         storages the convection velocity of atmosphere and LWC of SWD in         three-dimensional grid points with interval of 1 kilometer. IU         finds above values for specified training case by interpolation         in DU based on information from SM 1, ACDM 2, and FPMM 3. DCU         calculates the distance from starting position of simulation at         staring time to the position where the LWC of SWD is high enough         up to the icing conditions and sends the result to AIPM 13.     -   VSM 11 displays cloud and ice layer on aircraft based on         information from SM 1, ACDM 2, FPMM 3, FSSM 4, ISMSM 5, and FESM         6 on screen, where the icing zone's color is white and non-icing         zone's color is grey. Displayed time is local time.     -   PWAM 12 is a motor driven chair, which can pitch and row         according to data of force and momentum from FESM 6.     -   AIPM 13 displays information and data from SM 1, ACDM 2, FPMM 3,         FSSM 4, ISMSM 5, FESM 6 ASM 8, EHDSM 9, DCM 10.     -   BBM 14 records all information in flight.     -   DDTSM transfers all signals about flying state and other         information such as force, momentum to VSM 11, PWAM 12, AIPM 13.         All data and information transfer among all modules and units is         implemented with this module. 

1. A flight-icing simulator, for simulating the state of an aircraft being or being on the point of icing in flight and is used to train pilots to control and take steps under this state, includes the following modules SM (Startup Module) 1; ACDM (Atmosphere Condition Database Module) 2; FPMM (Flying Parameter Memory Module) 3; FSSM (Flight-icing State Simulation Module) 4; ISMSM (Icing Sensor Matrix Simulation Module) 5; FESM (Flight-icing Effect Simulation Module) 6; DDTSM (Dynamic Data Transmission Simulation Module) 7; ASM (Alarm Simulation Module) 8; EHDSM (Electrical Heating De-icing Simulation Module) 9; DCM (Distance Calculation Module) 10; VSM (Visual Simulation Module) 11; PWAM (Pilot Work Area Module) 12; AIPM (Aviation Instrument Panel Module) 13; BBM (Black Box Module)
 14. 2. A flight-icing simulator according to claim 1 wherein said FSSM(Flight-icing State Simulation Module) 4 includes the following four units OSOBMU (Original Snapshot's Orthogonal Base Memory Unit); OSCCMMU (Original Snapshot's Characteristic Coefficient Matrix Memory Unit); IU (Interpolation Unit); ISCU (Icing State Calculation Unit).
 3. A flight-icing simulator according to claim 1 wherein said FESM(Flight-icing Effect Simulation Module) 6 includes the following three units LPSU (Loading Point Selection Unit) FIU (Force Integration Unit); MIU (Momentum Integration Unit).
 4. A flight-icing simulator according to claim 1 wherein said EHDSM (Electrical Heating De-icing Simulation Module) 9 includes the following three units MSHTCU (Metal Skin Heat Transfer Calculation Unit); ILHCCU (Ice Layer Heat Conduction Calculation Unit); DECU (Deicing Effect Calculation Unit).
 5. A flight-icing simulator according to claim 1 wherein said DCM(Distance Calculation Module) 10 includes the following three units DU (Database Unit for the relationship of air convection velocity and LWC of SWD); IU (Interpolation Unit); DCU (Distance Calculation Unit). 